This invention relates to a highly efficient, incendiary high explosive, light armor penetrating 12.7 mm (0.50") caliber projectile.
"Light armor" as used herein means armor having a resistance to penetration equivalent to less than 0.50" of rolled homogeneous armor plate at 100 meters.
"Parasitic mass" as used herein means mass which provides no propulsion to the projectile and which provides an inefficient deposition of energy on or within an impacted target. In order to design such a projectile, it is necessary to reduce its parasitic mass to a minimum. Lead, because of its softness and malleability, is an inefficient depositor of energy because it deforms so easily against the hard substance of such target materials as steel.
"Targets" as used herein mean inanimate armored objects such as vehicles or aircraft.
Past attempts at a multipurpose 0.50" caliber multipurpose ammunition round include the round disclosed in U.S. Pat. No. 4,353,302 issued Oct. 12, 1982 to Kaare R. Strandli and assigned to A/S Raufoss Ammunisjonsfabrikker of Raufoss, Norway. That round had a high density subcaliber penetrator in a hardened, high-explosive filled tubular steel body and a nose incendiary ignitable by impact with a target to in turn ignite the explosive after a suitable time delay. Upon testing, it has been found that further improvement in the round is desirable to achieve effectiveness on certain targets.
The projectile of the invention has a copper jacket surrounding a tubular hard, heavy metal inner core filled with explosive and has a nose filled with an ignitive mixture. By "hard, heavy metal" is meant tungsten, tungsten carbide, depleted uranium and the like. By "lightweight metal" is meant a metal that is lighter than "hard heavy metals". The rear end of the tube is an active (i.e. ignitable) metal such as aluminum, magnesium, or zirconium. In back of the active metal plug is a thin shield of lead. The use of each of the components will now be described. Existing weapon systems are designed for use with a copper jacket. Thus, it is necessary for the projectile to have a copper jacket in order to adequately interface with these weapon systems. The copper jacket engages the lands and grooves of the existing weapon system and spins-up and is thus stabilized in order to follow a true path to its intended target. The hard heavy metal tube has several functions. During the free flight condition, the hard heavy metal tube has a high polar moment of inertia and thus provides a high degree of stability to the projectile. This stability provides a very accurate projectile as a result. On impact with the target, the high density of the material in combination with its design of high sectional density provides a very effective means of penetrating the target. The ignitor mixture provides a measurable delay subsequent to which the explosive is detonated inside the target. Upon detonation of the explosive, the active metal which forms the base plug of the projectile becomes part of the explosive reaction and becomes ignited. One of the principle attributes of this active metal is that it burns for a relatively long time. Thus, if any fuel vapors are present, the burning active metal will help ignite them. The optional thin lead shield at the rear end of the projectile provides a seal which prevents the hot powder gases which propel the projectile from prematurely igniting the contents of the projectile.